What size lrr tires for my 95 jeep cherokee sport 2wd? I want sMaller than 225 75 15

[95CHERJUST]

my jeep cherokee has 235 75 15 tires. I want max fe so stock size is 225 75 15 what do you recommen so i can lower the jeep more and get skinnier tires that are lrr like goodyear viva or wr g2 noikian thanks for ure help.

[CapriRacer]

There's a number of reasons why you don't want to go smaller than the stock size - and fuel economy is one of them.

As a general rule, tires with more load carrying capacity - and that generally means larger diameter - get ever so slightly better rolling resistance - all other things being equal.

[95CHERJUST]

Doesnt make sense to me.

I have a 15 inch wheel and stock size is 225 75 15, so if i go smaller than that wont my jeep be lower to the ground for better FE? I understand load and tire size in reference but cant i look at each tires load resistance?

Also my jeep is realli light, nothing inside of it but drivers seat and no excess suspension or hitch and has aluminum wheels at 50psi.

so want to go low resistence tires and want to know what size and brand to go to. thats all

[Hermie]

Depends on what dimention you want smaller.

The numbers on the tire means as follows:

225: Your tread width in millimeters

75: Profile (how much tire there is above the rim), measured in percent of tread width. In this case, the height of the tire above the rim is 75% of 225 mm.

15: Rim diameter in inches.

What you DON'T want to do is get smaller diameter tires, for example, going from 75 to 70. This will increase acceleration by a small margin, but at the expense of top speed (which probably doesn't matter) as well as hurt fuel economy. Larger diameter tires will simulate your final gear being larger, resulting in lower RPMs, which means better fuel economy.

What will increase FE by decreasing drag would be narrower tires- 205 instead of 225, for example- But the drawback is reduced traction.

If you want better cornering, you could go with larger rims. These will simulate stiffer sidewalls. Not sure what they'll do for FE, though.

[CapriRacer]

Originally Posted by 95CHERJUST

Doesnt make sense to me.

I have a 15 inch wheel and stock size is 225 75 15, so if i go smaller than that wont my jeep be lower to the ground for better FE?

............

Lower to the ground does not always equal better fuel economy.

Originally Posted by 95CHERJUST

..........

I understand load and tire size in reference but cant i look at each tires load resistance?

..........

No. Load carrying capacity has no relation to rolling resistance - except to say that as the load goes up, the rolling resistance goes up. But if you keep the same load (like replacing the tire on a particular vehicle), then as the load carrying capacity goes up, the rolling resistance goes down ever so slightly - all other things being equal.

[zjrog]

I was wondering what the outcome of this was for the OP?

Might I suggest... The smaller a tire is in diameter, equals a tire that won't roll as far per revolution as a larger diameter tire. As mentioned this wil effect your effective final gear ratios. A shorter tire will be perceived as making the Jeep more "quick", but will also use more fuel as the engine needs to spin faster to maintain speed. Keeping the stock/OEM size will keep your speedo correct as well.

Conversely, moving to a taller tire (within limits) will slow the engine down. A taller tire might also be a wider tire so you might actually INCREASE rolling resistance. AND! Don't always assume an alloy wheel is lighter. Especially on a Jeep.

So I had to make a trade-off. MY Jeep spends more time on the road than the trail. Fact of life. Sure, I WANTED bigger tires, but settled for the 31" sizes. A good tradeoff for how I drive on the highway and on the trails. (besides, my 4 banger Ford Ranger 4x4 on 33" tires for now, 35s in its future, will crawl better than my Jeep, just not as comfortable)

I'll even make a suggestion for a tire. Well, size at least. It will be a bit tight of a fit for stock Cherokee. I know there are sizes for duals out there, in a bout a 235/85-15. Perhaps there is a similar 225 tire. They are made for higher pressures anyway, and can be had in a road tread and traction tread. They will be a bit pricey though. But you will get a taller tire, with a relatively narrow tread (YES ,m I know 235 is wider than 225...), with high pressure ratings and lower rolling resistance. I believe that will work pretty well, as your Jeep is a lot lighter than 1 tron trucks and loads these tires are designed for. I'll be honest that I SERIOUSLY considered just these sorts of tires for my Jeep, but chose a regular 31" tire in All Terrain tread for what I do.

One last thing. My daughter drives a 1990 Cherokee. No lift, and I have it riding on 235/75-15s, with 3.55 gears and steel wheels. The Jeep is bright yellow, stands out, so she drives very conservatively (sometimes I'm a pretty smart Dad!!!). Over the course of the summer, she was getting 23-26 MPG. Depending on where she went and how much was highway... The WORST she got all summer was 19...

[firdale]

Excellent thread. Great to see cherokee's averaging mid 20's. That's what I'm shooting for. Just got a 96 cherokee I6 auto. Careful driving was netting about 20 mpg. Got new tires last week, 205x75x15 with studs (suppose to have been an option on the cherokee at some point), and averaged right at 1.5 mpg more on trip across state this weekend. Best tank of five yielded 23.8.
Was pretty excited about the aero mods, but on one leg of the trip we bucked 20 + mph headwinds for 187 miles at 60-65 mph (usually keep it under 60) and milage only dropped to 19.8. I know it's not that simple, but if fighting strong headwinds and going faster drops FE less than 2mpg, maybe there are mods that would be more productive.
Am going to modify the air intake next and see if that makes a difference.

[slowmover]

Originally Posted by firdale

Excellent thread. Great to see cherokee's averaging mid 20's. That's what I'm shooting for. Just got a 96 cherokee I6 auto. Careful driving was netting about 20 mpg. Got new tires last week, 205x75x15 with studs (suppose to have been an option on the cherokee at some point), and averaged right at 1.5 mpg more on trip across state this weekend. Best tank of five yielded 23.8.
Was pretty excited about the aero mods, but on one leg of the trip we bucked 20 + mph headwinds for 187 miles at 60-65 mph (usually keep it under 60) and milage only dropped to 19.8. I know it's not that simple, but if fighting strong headwinds and going faster drops FE less than 2mpg, maybe there are mods that would be more productive.
Am going to modify the air intake next and see if that makes a difference.

Nice numbers, congrats. As they say on the vehicle-specific enthusiast boards, Fill out your signature with the truck specifications. A 4WD is different than a 2WD, an auto from a manual, etc.

Spent the weekend wrenching on the usual Jeep reliability culprits. Try the NAXJA board for issues if not already familiar. Cheap to buy, cheap to run, and cheap to fix. Hard to beat a well-chosen XJ.

As to tires I went to a barely taller, but wider tire years back on our XJ's. Now want to return to the stock 225-70/16 as mpg was better, as was ride (now currently have an LT tire that ruined the ride however much handling was improved). Am looking at the MICHELIN Symmetry as it looks as though a tire life of 80k miles is easy, and, as an LRR passenger car tire, it fits in all ways with weight specs, etc, to be encountered on our '01 2WD Limited and the way we use it (now and foreseeable).

As to the air intake (and filter size, etc) search for a HP calculator and you'll see that the stock airbox is plenty good for the rated power. I believe that an upgrade to the traditionally sloppy Jeep steering is a way to improve overall FE and reliability/performance as bang for the buck. Same was true for polyurethane bushings on the shock absorbers and FF/RR antiroll bars.

There is also a nice thread hereabouts on aeromodding an Cherokee XJ.

.